Also, it's or it's not his or her or my or our or their funeral. One must take the consequences of one's destructive or foolish actions. This expression is used to show one's contempt or lack of sympathy for another's actions. For example, Suppose they do get pulled over for taking a joy ride—It's their funeral, or I don't care whether you quit your job—it's not my funeral. This hyperbolic term implies that an action is so bad it will result in death. [Slang; mid-1800s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.